reviewer's feedback: SQLite: now using static strings + bound parameters

platform/firefox/vapi-background.js

@@ -93,51 +93,53 @@ window.addEventListener('unload', function() {
 
 /******************************************************************************/
 
-var SQLite = {
+// API matches that of chrome.storage.local:
-    open: function() {
+//   https://developer.chrome.com/extensions/storage
+
+vAPI.storage = (function() {
+    var db = null;
+
+    var close = function() {
+        if ( db === null ) {
+            return;
+        }
+        db.createStatement('VACUUM').executeAsync();
+        db.asyncClose();
+        db = null;
+    };
+
+    var open = function() {
+        if ( db !== null ) {
+            return;
+        }
+
+        // Create path
         var path = Services.dirsvc.get('ProfD', Ci.nsIFile);
         path.append('extension-data');
-
         if ( !path.exists() ) {
             path.create(Ci.nsIFile.DIRECTORY_TYPE, parseInt('0774', 8));
         }
-
         if ( !path.isDirectory() ) {
             throw Error('Should be a directory...');
         }
-
         path.append(location.host + '.sqlite');
-        this.db = Services.storage.openDatabase(path);
-        this.db.executeSimpleSQL(
-            'CREATE TABLE IF NOT EXISTS settings' +
-            '(name TEXT PRIMARY KEY NOT NULL, value TEXT);'
-        );
 
-        cleanupTasks.push(function() {
+        // Open database
-            // VACUUM somewhere else, instead on unload?
+        db = Services.storage.openDatabase(path);
-            SQLite.run('VACUUM');
-            SQLite.db.asyncClose();
-        });
-    },
 
-    run: function(query, values, callback) {
+        // Database was opened, register cleanup task
-        if ( !this.db ) {
+        cleanupTasks.push(close);
-            this.open();
-        }
 
+        // Setup database
+        db.createAsyncStatement('CREATE TABLE IF NOT EXISTS settings(name TEXT PRIMARY KEY NOT NULL, value TEXT);')
+          .executeAsync();
+    };
+
+    // Execute a query
+    var runStatement = function(stmt, callback) {
         var result = {};
 
-        query = this.db.createAsyncStatement(query);
+        stmt.executeAsync({
-
-        if ( Array.isArray(values) && values.length ) {
-            var i = values.length;
-
-            while ( i-- ) {
-                query.bindByIndex(i, values[i]);
-            }
-        }
-
-        query.executeAsync({
             handleResult: function(rows) {
                 if ( !rows || typeof callback !== 'function' ) {
                     return;
@@ -160,120 +162,139 @@ var SQLite = {
                 console.error('SQLite error ', error.result, error.message);
             }
         });
+    };
+
+    var bindNames = function(stmt, names) {
+        if ( Array.isArray(names) === false || names.length === 0 ) {
+            return;
         }
-};
+        var params = stmt.newBindingParamsArray();
-
+        var i = names.length, bp;
-/******************************************************************************/
+        while ( i-- ) {
-
+            bp = params.newBindingParams();
-vAPI.storage = {
+            bp.bindByName('name', names[i]);
-    QUOTA_BYTES: 100 * 1024 * 1024,
+            params.addParams(bp);
-
-    sqlWhere: function(col, params) {
-        if ( params > 0 ) {
-            params = new Array(params + 1).join('?, ').slice(0, -2);
-            return ' WHERE ' + col + ' IN (' + params + ')';
         }
+        stmt.bindParameters(params);
+    };
 
-        return '';
+    var clear = function(callback) {
-    },
+        if ( db === null ) {
+            open();
+        }
+        runStatement(db.createStatement('DELETE FROM settings; VACUUM;'), callback);
+    };
 
-    get: function(details, callback) {
+    var getBytesInUse = function(keys, callback) {
         if ( typeof callback !== 'function' ) {
             return;
         }
 
-        var values = [], defaults = false;
+        if ( db === null ) {
+            open();
+        }
 
+        var stmt;
+        if ( Array.isArray(keys) ) {
+            stmt = db.createStatement('SELECT "size" AS size, SUM(LENGTH(value)) FROM settings WHERE name = :name');
+            bindNames(keys);
+        } else {
+            stmt = db.createStatement('SELECT "size" AS size, SUM(LENGTH(value)) FROM settings');
+        }
+
+        runStatement(stmt, function(result) {
+            callback(result.size);
+        });
+    };
+
+    var read = function(details, callback) {
+        if ( typeof callback !== 'function' ) {
+            return;
+        }
+
+        if ( db === null ) {
+            open();
+        }
+
+        var names = [];
         if ( details !== null ) {
             if ( Array.isArray(details) ) {
-                values = details;
+                names = details;
             } else if ( typeof details === 'object' ) {
-                defaults = true;
+                names = Object.keys(details);
-                values = Object.keys(details);
             } else {
-                values = [details.toString()];
+                names = [details.toString()];
             }
         }
 
-        SQLite.run(
+        var stmt;
-            'SELECT * FROM settings' + this.sqlWhere('name', values.length),
+        if ( names.length === 0 ) {
-            values,
+            stmt = db.createStatement('SELECT * FROM settings');
-            function(result) {
+        } else {
+            stmt = db.createStatement('SELECT * FROM settings WHERE name = :name');
+            bindNames(stmt, names);
+        }
+
+        runStatement(stmt, function(result) {
             var key;
-
             for ( key in result ) {
                 result[key] = JSON.parse(result[key]);
             }
-
+            if ( typeof details === 'object' && details !== null ) {
-                if ( defaults ) {
                 for ( key in details ) {
-                        if ( result[key] === undefined ) {
+                    if ( result.hasOwnProperty(key) === false ) {
                         result[key] = details[key];
                     }
                 }
             }
-
             callback(result);
+        });
+    };
+
+    var remove = function(keys, callback) {
+        if ( db === null ) {
+            open();
         }
-        );
+        var stmt = db.createStatement('DELETE FROM settings WHERE name = :name');
-    },
+        bindNames(stmt, typeof keys === 'string' ? [keys] : keys);
+        runStatement(stmt, callback);
+    };
 
-    set: function(details, callback) {
+    var write = function(details, callback) {
-        var key, values = [], placeholders = [];
+        if ( db === null ) {
+            open();
+        }
 
-        for ( key in details ) {
+        var stmt = db.createStatement('INSERT OR REPLACE INTO settings (name, value) VALUES(:name, :value)');
-            if ( !details.hasOwnProperty(key) ) {
+        var params = stmt.newBindingParamsArray(), bp;
+        for ( var key in details ) {
+            if ( details.hasOwnProperty(key) === false ) {
                 continue;
             }
-            values.push(key);
+            bp = params.newBindingParams();
-            values.push(JSON.stringify(details[key]));
+            bp.bindByName('name', key);
-            placeholders.push('?, ?');
+            bp.bindByName('value', JSON.stringify(details[key]));
+            params.addParams(bp);
         }
-
+        if ( params.length === 0 ) {
-        if ( !values.length ) {
             return;
         }
 
-        SQLite.run(
+        stmt.bindParameters(params);
-            'INSERT OR REPLACE INTO settings (name, value) SELECT ' +
+        runStatement(stmt, callback);
-                placeholders.join(' UNION SELECT '),
+    };
-            values,
-            callback
-        );
-    },
 
-    remove: function(keys, callback) {
+    // Export API
-        if ( typeof keys === 'string' ) {
+    var api = {
-            keys = [keys];
+        QUOTA_BYTES: 100 * 1024 * 1024,
-        }
+        clear: clear,
-
+        get: read,
-        SQLite.run(
+        getBytesInUse: getBytesInUse,
-            'DELETE FROM settings' + this.sqlWhere('name', keys.length),
+        remove: remove,
-            keys,
+        set: write
-            callback
+    };
-        );
+    return api;
-    },
+})();
-
-    clear: function(callback) {
-        SQLite.run('DELETE FROM settings');
-        SQLite.run('VACUUM', null, callback);
-    },
-
-    getBytesInUse: function(keys, callback) {
-        if ( typeof callback !== 'function' ) {
-            return;
-        }
-
-        SQLite.run(
-            'SELECT "size" AS size, SUM(LENGTH(value)) FROM settings' +
-                this.sqlWhere('name', Array.isArray(keys) ? keys.length : 0),
-            keys,
-            function(result) {
-                callback(result.size);
-            }
-        );
-    }
-};
 
 /******************************************************************************/